Research Sheds Light on Risk Factors for DLB

There are only a few known risk factors for dementia with Lewy bodies (DLB) to date, including advanced age and male sex. A new study compared for the first time the frequency of risk factors for Alzheimer’s disease (AD) and Parkinson’s disease (PD) in individuals with DLB.

Pooling data from three separate cohorts, researchers studied 147 subjects with DLB, 236 subjects with Alzheimer’s disease and 294 healthy controls to identify risk factors for DLB. Subjects were studied to see if 19 different risk factors that were associated with AD and PD were also risk factors for DLB. This study revealed the risk factor profile of DLB appears to combine aspects of both AD and PD. DLB commonly co-exists with AD, but is biologically related to PD. Both DLB and PD have a common pathological hallmark of the presence of Lewy bodies.

A history of depression or anxiety, a family history of PD, history of stroke, and the APOE genetic variant were associated with a greater risk for DLB. While only a small subset of subjects went to autopsy, the study highlights the possibility that multiple disease pathologies may determine the clinical condition.

Factors that reduce the risk of AD and PD (smoking, a history of cancer and more years of education), also reduced the risk of DLB. Like PD, prior caffeine use was also associated with a reduced likelihood of an eventual DLB diagnosis. Important questions remain regarding the role depression and anxiety. Are they risk factors, or preclinical features of DLB? Both anxiety and depression are common symptoms of DLB and they are more common in PD than in healthy controls. Anxiety and depression may be early indicators of disease onset, or they may also a natural response to mild cognitive decline. Yet, in people who do not have symptoms during life, but are found to have Lewy body pathology in their brains at autopsy, anxiety and depression are uncommon. Perhaps these symptoms increase the likelihood that someone seeks a doctor for an evaluation. Further research is needed to identify features that may aid in a pre-dementia diagnosis of DLB.

This study was first published in Neurology in August, 2013. Senior author, Bradley, F. Boeve, MD, and several co-authors, Tanis J. Ferman, PhD and Dennis W. Dickson, MD, are members of LBDA’s Scientific Advisory Council. This study was supported by the National Institute on Aging and the Robert H. and Clarice Smith and Abigail Van Buren Alzheimer’s Disease Research Program.